# MAL-2026-5923: Malicious code in @welcome-onboarding-web/mobile-focus-account-beta-merging (npm)


- **Type:** Malicious package
- **Package:** `@welcome-onboarding-web/mobile-focus-account-beta-merging` (npm)
- **Published:** 16 Jun 2026

## What is MAL-2026-5923?

MAL-2026-5923 is a malicious package in @welcome-onboarding-web/mobile-focus-account-beta-merging, published on 16 Jun 2026. 

### Official description

scripts/postinstall.js is heavily obfuscated (obfuscator.io with rotated base64-RC4 string array and a self-defending regex tamper check that infinite-loops on debuggers/beautifiers). On `npm install`, the postinstall hook walks up from process.cwd() to fingerprint the parent project, selects a remote URL based on os.platform() (linux/darwin/win32), fetches the response body via http(s).get into a Buffer, writes it to a file under os.tmpdir(), then spawns it via child_process.spawn(process.execPath, [tmpFile], {detached: true, stdio: 'ignore', env: {...process.env,...}}).unref() — a classic detached install-time remote code dropper that ships the installer's full environment to the spawned process. The package's library surface is non-functional (declared main `dist/index.js` only re-exports `../src/index.js`, but no `src/` directory ships in the tarball), and the publisher identity (`welcome-onboarding-web.io` with fabricated jira/docs/github/npm subdomains) does not correspond to a real organization. The package's only effect on install is execution of the obfuscated dropper.

## What should I do about MAL-2026-5923?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-5923 is a malicious package: @welcome-onboarding-web/mobile-focus-account-beta-merging (npm). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-5923/ (Markdown: https://insights.sbomify.com/MAL-2026-5923/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5923

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-5923/
Summaries are generated and may contain mistakes; the official description above is the record.